X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=49074cee9c20d6a1bb9ff733394c7a966115d42e;hp=5a72d6b06d391eb3b9fc826f3c07eca4d9f5c6e1;hb=ba85c59d96d962dddaa0f1a2608ebea2e8ae694b;hpb=cd27ed9a7460ccfa6106b190f46beb89c2f3150d diff --git a/src/search.cpp b/src/search.cpp index 5a72d6b0..49074cee 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -175,7 +175,6 @@ namespace { // Node counters, used only by thread[0] but try to keep in different cache // lines (64 bytes each) from the heavy multi-thread read accessed variables. - bool SendSearchedNodes; int NodesSincePoll; int NodesBetweenPolls = 30000; @@ -367,7 +366,7 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { static Book book; // Initialize global search-related variables - StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = SendSearchedNodes = false; + StopOnPonderhit = StopRequest = QuitRequest = AspirationFailLow = false; NodesSincePoll = 0; current_search_time(get_system_time()); Limits = limits; @@ -410,7 +409,8 @@ bool think(Position& pos, const SearchLimits& limits, Move searchMoves[]) { read_evaluation_uci_options(pos.side_to_move()); Threads.read_uci_options(); - // If needed allocate pawn and material hash tables and adjust TT size + // Allocate pawn and material hash tables if number of active threads + // increased and set a new TT size if changed. Threads.init_hash_tables(); TT.set_size(Options["Hash"].value()); @@ -712,7 +712,7 @@ namespace { Depth ext, newDepth; ValueType vt; Value bestValue, value, oldAlpha; - Value refinedValue, nullValue, futilityBase, futilityValueScaled; // Non-PV specific + Value refinedValue, nullValue, futilityBase, futilityValue; bool isPvMove, inCheck, singularExtensionNode, givesCheck, captureOrPromotion, dangerous; int moveCount = 0, playedMoveCount = 0; Thread& thread = Threads[pos.thread()]; @@ -995,14 +995,6 @@ split_point_start: // At split points actual search starts from here // Save the current node count before the move is searched nodes = pos.nodes_searched(); - // If it's time to send nodes info, do it here where we have the - // correct accumulated node counts searched by each thread. - if (!SpNode && SendSearchedNodes) - { - SendSearchedNodes = false; - cout << "info" << speed_to_uci(pos.nodes_searched()) << endl; - } - // For long searches send current move info to GUI if (pos.thread() == 0 && current_search_time() > 2000) cout << "info" << depth_to_uci(depth) @@ -1070,19 +1062,19 @@ split_point_start: // At split points actual search starts from here // We illogically ignore reduction condition depth >= 3*ONE_PLY for predicted depth, // but fixing this made program slightly weaker. Depth predictedDepth = newDepth - reduction(depth, moveCount); - futilityValueScaled = futilityBase + futility_margin(predictedDepth, moveCount) - + H.gain(pos.piece_on(move_from(move)), move_to(move)); + futilityValue = futilityBase + futility_margin(predictedDepth, moveCount) + + H.gain(pos.piece_on(move_from(move)), move_to(move)); - if (futilityValueScaled < beta) + if (futilityValue < beta) { if (SpNode) { lock_grab(&(sp->lock)); - if (futilityValueScaled > sp->bestValue) - sp->bestValue = bestValue = futilityValueScaled; + if (futilityValue > sp->bestValue) + sp->bestValue = bestValue = futilityValue; } - else if (futilityValueScaled > bestValue) - bestValue = futilityValueScaled; + else if (futilityValue > bestValue) + bestValue = futilityValue; continue; } @@ -1228,8 +1220,8 @@ split_point_start: // At split points actual search starts from here && Threads.available_slave_exists(pos.thread()) && !StopRequest && !thread.cutoff_occurred()) - Threads.split(pos, ss, &alpha, beta, &bestValue, depth, - threatMove, moveCount, &mp, NT); + bestValue = Threads.split(pos, ss, alpha, beta, bestValue, depth, + threatMove, moveCount, &mp, NT); } // Step 20. Check for mate and stalemate @@ -1298,6 +1290,7 @@ split_point_start: // At split points actual search starts from here bool inCheck, enoughMaterial, givesCheck, evasionPrunable; const TTEntry* tte; Depth ttDepth; + ValueType vt; Value oldAlpha = alpha; ss->bestMove = ss->currentMove = MOVE_NONE; @@ -1368,7 +1361,7 @@ split_point_start: // At split points actual search starts from here CheckInfo ci(pos); // Loop through the moves until no moves remain or a beta cutoff occurs - while ( alpha < beta + while ( bestValue < beta && (move = mp.get_next_move()) != MOVE_NONE) { assert(move_is_ok(move)); @@ -1388,10 +1381,11 @@ split_point_start: // At split points actual search starts from here + piece_value_endgame(pos.piece_on(move_to(move))) + (move_is_ep(move) ? PawnValueEndgame : VALUE_ZERO); - if (futilityValue < alpha) + if (futilityValue < beta) { if (futilityValue > bestValue) bestValue = futilityValue; + continue; } @@ -1450,11 +1444,12 @@ split_point_start: // At split points actual search starts from here if (value > bestValue) { bestValue = value; - if (value > alpha) - { + ss->bestMove = move; + + if ( PvNode + && value > alpha + && value < beta) // We want always alpha < beta alpha = value; - ss->bestMove = move; - } } } @@ -1464,8 +1459,11 @@ split_point_start: // At split points actual search starts from here return value_mated_in(ss->ply); // Update transposition table - ValueType vt = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT); - TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, ss->bestMove, ss->eval, evalMargin); + move = bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove; + vt = bestValue <= oldAlpha ? VALUE_TYPE_UPPER + : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT; + + TT.store(pos.get_key(), value_to_tt(bestValue, ss->ply), vt, ttDepth, move, ss->eval, evalMargin); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1945,9 +1943,6 @@ split_point_start: // At split points actual search starts from here dbg_print_mean(); dbg_print_hit_rate(); - - // Send info on searched nodes as soon as we return to root - SendSearchedNodes = true; } // Should we stop the search? @@ -2135,71 +2130,79 @@ split_point_start: // At split points actual search starts from here } // namespace -// ThreadsManager::idle_loop() is where the threads are parked when they have no work -// to do. The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint -// object for which the current thread is the master. +// Little helper used by idle_loop() to check that all the slaves of a +// master thread have finished searching. -void ThreadsManager::idle_loop(int threadID, SplitPoint* sp) { +static bool all_slaves_finished(SplitPoint* sp) { - assert(threadID >= 0 && threadID < MAX_THREADS); + assert(sp); - int i; - bool allFinished; + for (int i = 0; i < Threads.size(); i++) + if (sp->is_slave[i]) + return false; + + return true; +} + + +// Thread::idle_loop() is where the thread is parked when it has no work to do. +// The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint object +// for which the thread is the master. + +void Thread::idle_loop(SplitPoint* sp) { while (true) { - // Slave threads can exit as soon as AllThreadsShouldExit raises, - // master should exit as last one. - if (allThreadsShouldExit) - { - assert(!sp); - threads[threadID].state = Thread::TERMINATED; - return; - } - - // If we are not thinking, wait for a condition to be signaled + // If we are not searching, wait for a condition to be signaled // instead of wasting CPU time polling for work. - while ( threadID >= activeThreads - || threads[threadID].state == Thread::INITIALIZING - || (useSleepingThreads && threads[threadID].state == Thread::AVAILABLE)) + while ( do_sleep + || do_terminate + || (Threads.use_sleeping_threads() && state == Thread::AVAILABLE)) { - assert(!sp || useSleepingThreads); - assert(threadID != 0 || useSleepingThreads); + assert(!sp || Threads.use_sleeping_threads()); + assert(threadID != 0 || Threads.use_sleeping_threads()); - if (threads[threadID].state == Thread::INITIALIZING) - threads[threadID].state = Thread::AVAILABLE; + // Slave thread should exit as soon as do_terminate flag raises + if (do_terminate) + { + assert(!sp); + state = Thread::TERMINATED; + return; + } - // Grab the lock to avoid races with Thread::wake_up() - lock_grab(&threads[threadID].sleepLock); + if (state == Thread::INITIALIZING) + state = Thread::AVAILABLE; - // If we are master and all slaves have finished do not go to sleep - for (i = 0; sp && i < activeThreads && !sp->is_slave[i]; i++) {} - allFinished = (i == activeThreads); + // Grab the lock to avoid races with Thread::wake_up() + lock_grab(&sleepLock); - if (allFinished || allThreadsShouldExit) + // If we are master and all slaves have finished don't go to sleep + if (sp && all_slaves_finished(sp)) { - lock_release(&threads[threadID].sleepLock); + lock_release(&sleepLock); break; } - // Do sleep here after retesting sleep conditions - if (threadID >= activeThreads || threads[threadID].state == Thread::AVAILABLE) - cond_wait(&threads[threadID].sleepCond, &threads[threadID].sleepLock); + // Do sleep after retesting sleep conditions under lock protection, in + // particular we need to avoid a deadlock in case a master thread has, + // in the meanwhile, allocated us and sent the wake_up() call before we + // had the chance to grab the lock. + if (do_sleep || state == Thread::AVAILABLE) + cond_wait(&sleepCond, &sleepLock); - lock_release(&threads[threadID].sleepLock); + lock_release(&sleepLock); } // If this thread has been assigned work, launch a search - if (threads[threadID].state == Thread::WORKISWAITING) + if (state == Thread::WORKISWAITING) { - assert(!allThreadsShouldExit); + assert(!do_terminate); - threads[threadID].state = Thread::SEARCHING; + state = Thread::SEARCHING; // Copy split point position and search stack and call search() - // with SplitPoint template parameter set to true. SearchStack ss[PLY_MAX_PLUS_2]; - SplitPoint* tsp = threads[threadID].splitPoint; + SplitPoint* tsp = splitPoint; Position pos(*tsp->pos, threadID); memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack)); @@ -2214,35 +2217,26 @@ void ThreadsManager::idle_loop(int threadID, SplitPoint* sp) { else assert(false); - assert(threads[threadID].state == Thread::SEARCHING); + assert(state == Thread::SEARCHING); - threads[threadID].state = Thread::AVAILABLE; + state = Thread::AVAILABLE; // Wake up master thread so to allow it to return from the idle loop in // case we are the last slave of the split point. - if ( useSleepingThreads + if ( Threads.use_sleeping_threads() && threadID != tsp->master - && threads[tsp->master].state == Thread::AVAILABLE) - threads[tsp->master].wake_up(); + && Threads[tsp->master].state == Thread::AVAILABLE) + Threads[tsp->master].wake_up(); } // If this thread is the master of a split point and all slaves have // finished their work at this split point, return from the idle loop. - for (i = 0; sp && i < activeThreads && !sp->is_slave[i]; i++) {} - allFinished = (i == activeThreads); - - if (allFinished) + if (sp && all_slaves_finished(sp)) { - // Because sp->slaves[] is reset under lock protection, + // Because sp->is_slave[] is reset under lock protection, // be sure sp->lock has been released before to return. lock_grab(&(sp->lock)); lock_release(&(sp->lock)); - - // In helpful master concept a master can help only a sub-tree, and - // because here is all finished is not possible master is booked. - assert(threads[threadID].state == Thread::AVAILABLE); - - threads[threadID].state = Thread::SEARCHING; return; } }